Hi, Ric; The reference is the fragment "Vande spiegheling der singconst" which is up at the Huygens-Fokker site, in English. Fokker's introduction: <http://www.xs4all.nl/~huygensf/doc/stevinsp.html> Stevin's essay: <http://www.xs4all.nl/~huygensf/doc/singe.html> Clark
This PTG archive page provided courtesy of Moy Piano Service, LLC